By the way, I found that after I installed Node/npm, I could also (a) change from Java 16 to 17, and (b) update all the versions in the POM to their latest. The Vaadin tutorial app continued to run successfully after these updates.
So my POM looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<!-- Vaadin project from https://start.vaadin.com/project/53571864-5e36-488b-8d11-d91844066446 -->
<groupId>com.example.application</groupId>
<artifactId>flowcrmtutorial</artifactId>
<name>Project base for Spring Boot and Vaadin Flow</name>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<properties>
<java.version>17</java.version>
<vaadin.version>14.7.0</vaadin.version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.5</version>
</parent>
<repositories>
<!-- The order of definitions matters. Explicitly defining central here to make sure it has the highest priority. -->
<!-- Main Maven repository -->
<repository>
<id>central</id>
<url>https://repo.maven.apache.org/maven2</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
<!-- Repository used by many Vaadin add-ons -->
<repository>
<id>Vaadin Directory</id>
<url>https://maven.vaadin.com/vaadin-addons</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<!-- Main Maven repository -->
<pluginRepository>
<id>central</id>
<url>https://repo.maven.apache.org/maven2</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-bom</artifactId>
<version>${vaadin.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>com.vaadin</groupId>
<!-- Replace artifactId with vaadin-core to use only free components -->
<artifactId>vaadin</artifactId>
<exclusions>
<!-- Webjars are only needed when running in Vaadin 13 compatibility mode -->
<exclusion>
<groupId>com.vaadin.webjar</groupId>
<artifactId>*</artifactId>
</exclusion>
<exclusion>
<groupId>org.webjars.bowergithub.insites</groupId>
<artifactId>*</artifactId>
</exclusion>
<exclusion>
<groupId>org.webjars.bowergithub.polymer</groupId>
<artifactId>*</artifactId>
</exclusion>
<exclusion>
<groupId>org.webjars.bowergithub.polymerelements</groupId>
<artifactId>*</artifactId>
</exclusion>
<exclusion>
<groupId>org.webjars.bowergithub.vaadin</groupId>
<artifactId>*</artifactId>
</exclusion>
<exclusion>
<groupId>org.webjars.bowergithub.webcomponents</groupId>
<artifactId>*</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-spring-boot-starter</artifactId>
<exclusions>
<!-- Excluding so that webjars are not included. -->
<exclusion>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.vaadin.artur</groupId>
<artifactId>a-vaadin-helper</artifactId>
<version>1.7.2</version>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>exampledata</artifactId>
<version>4.0.0</version>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-testbench</artifactId>
<scope>test</scope>
</dependency>
<!-- Include JUnit 4 support for TestBench and others -->
<dependency>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.github.bonigarcia</groupId>
<artifactId>webdrivermanager</artifactId>
<version>5.0.3</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<defaultGoal>spring-boot:run</defaultGoal>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<!-- Clean build and startup time for Vaadin apps sometimes may exceed
the default Spring Boot's 30sec timeout. -->
<configuration>
<wait>500</wait>
<maxAttempts>240</maxAttempts>
</configuration>
</plugin>
<!--
Take care of synchronizing java dependencies and imports in
package.json and main.js files.
It also creates webpack.config.js if not exists yet.
-->
<plugin>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-maven-plugin</artifactId>
<version>${vaadin.version}</version>
<executions>
<execution>
<goals>
<goal>prepare-frontend</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<!-- Production mode is activated using -Pproduction -->
<id>production</id>
<build>
<plugins>
<plugin>
<groupId>com.vaadin</groupId>
<artifactId>vaadin-maven-plugin</artifactId>
<version>${vaadin.version}</version>
<executions>
<execution>
<goals>
<goal>build-frontend</goal>
</goals>
<phase>compile</phase>
</execution>
</executions>
<configuration>
<productionMode>true</productionMode>
<pnpmEnable>false</pnpmEnable>
</configuration>
</plugin>
</plugins>
</build>
</profile>
<profile>
<id>it</id>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<id>start-spring-boot</id>
<phase>pre-integration-test</phase>
<goals>
<goal>start</goal>
</goals>
</execution>
<execution>
<id>stop-spring-boot</id>
<phase>post-integration-test</phase>
<goals>
<goal>stop</goal>
</goals>
</execution>
</executions>
</plugin>
<!-- Runs the integration tests (*IT) after the server is started -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-failsafe-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>integration-test</goal>
<goal>verify</goal>
</goals>
</execution>
</executions>
<configuration>
<trimStackTrace>false</trimStackTrace>
<enableAssertions>true</enableAssertions>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
</project>